PURPOSE: We performed this study to evaluate the prognostic factors and the effect of induction chemotherapy in locally advanced non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: A retrospective analysis was done for 130 patients with locally advanced NSCLC treated with curative radiotherapy alone or induction chemo-radiotherapy from January 1986 to October 1996. Eighty-five patients were treated with radiotherapy alone, forty-five with induction chemotherapy and radiotherapy. Age, sex, performance status, histopathologic type, and stage were evenly distributed in both groups. The patients were treated with 6 MV or 10 MV X-ray. Conventional fractionation with daily fraction size 1.8~2.0 Gy was done. Of the patients, 129 patients received total dose above 59.6 Gy (56~66 Gy, median 60 Gy). Induction chemotherapy regimen were CAP (Cyclophosphamide, Adriamycin, Cisplatin) in 6 patients, MVP (Mitomycin, Vinblastine, Cisplatin) in 9 patients, MIC (Mitomycin, Ifosfamide Cisplatin) in 13 patients, and EP (Etoposide, Cisplatin) in 17 patients. Chemotherapy was done in 2~5 cycles (median 2). RESULTS: Overall 1-, 2-, and 3-year survival rate (YSR) for all patients were 41.5%, 13.7%, and 7%, respectively (median survival time 11 months). According to treatment modality, median survival time, overall 1-, 2-, and 3-YSR were 9 months, 32.9%, 10.5%, 6% for radiotherapy alone group, and 14 months, 57.8%, 20%, 7.6% for induction chemotherapy group, respectively (p=0.0005). Complete response (CR) to overall treatments was 25% (21/84) in radiotherapy alone and 40.5% (17/42) in induction chemotherapy group (p=0.09). The prognostic factors affecting overall survival were hemoglobin level (p=0.04), NSE (neuron-specific enolase) level (p=0.004), and response to overall treatment(p= 0.004). According to treatment modalities, NSE (neuron-specific enolase) (p=0.006) and response to overall treatment (p=0.003) were associated with overall survival in radiotherapy alone group, and response to overall treatment (p=0.007) in induction chemotherapy group. The failure pattern analysis revealed no significant difference between treatment modalities. But, in patients with CR to overall treatment, distant metastasis were found in 11/19 patients with radiotherapy alone, and 3/13 patients with induction chemotherapy and radiotherapy (p=0.07). Locoregional failure patterns were not different between two groups (10/19 vs 6/13). CONCLUSION: Induction chemotherapy and radiotherapy achieved increased 2YSR compared to radio therapy alone. At least in CR patients, there was decreased tendency in distant metastasis with induction chemotherapy. But, locoregional failures and long-term survival were not improved. Thus, there is need of more effort to increasing local control and further decreasing distant metastasis.